Bristol 411 Running Rich

[Martin9645]

Good afternoon all,

I have my Bristol 411 6.3l Mark 1 back on the road after a re-commission by Smallman Hall, Bridgnorth (cant recomend enough). Replacing all brakes, Electric Fuel Pump, all Seals (No Leaks!!), Fuel sender and Full Service.

However it is still running very rich and killing Polar Bears and melting icebergs in my wake.

The carb is 56 Years old (Carter AFB)

Q. Is it worth having the carb stripped and rebuilt replacing jets, floats springs etc.. Or would you recomend replacing for a NEW carb? Any recomendations??

Am getting 12 miles per gallon which I am quite pleased with

many thanks

[PaulS]

Hello there,

I’d recommend full replacement with a new Edelbrock carburetor which will work nicely straight out of the box. The Edelbrock is effectively a modern version of the AFB so should swap without issue and deliver the same performance as factory and much better than your existing.

Obviously keep your original. 😀

That’s my tuppence.

Paul Stephenson
Houston, Tx
Former owner 1971 411s2

[Geoff Kingston]

If you are going for a replacement the best option is one of the Edelbrock carbs and preferably with a manual choke which I found much better on my 411/3 and on my Range Rover LSE which we recently converted from EFI to Carb.
With the Edelbrock you will also need the kick down conversion kit for the Chrysler engine/gearbox installation which is not expensive and from memory straight forward to fit.
If you do fancy doing a rebuild I attach a link to a US supplier who should be able to sell you the correct rebuild kit for your existing Carb, I have bought parts from him for the Carter on my 603E and they arrived within a week which was excellent, but my preference would be an new Edelbrock.
Geoff.

https://www.carburetor-parts.com/afb...r-rebuild-kits

[peter dowdle]

Martin there realy is only one carbie to concider that is an Edelbrock AVS2 with auto choke. Edelbrock took over carter years ago and have done a lot of development work to modenize their carbies but remain a direct swap for your Carter. The only real decisions you need to make is the finish ( I went for satin ). and what size . The 650 or the 500.The direct replacement is the 650 but their is plenty of people saying if you are just a touring driver the 500 is ok.

I am very happy with the 650 but I am told your fuel economy should improve with the 500.

[AndrewA]

Great link to the carb guy Geoff - thanks. He may be able to help with my outboard motor woes!

He also has some useful stuff to say about rich running Carter carbs.

https://www.carburetor-blog.com/know...20be%20damaged.

[Kevin H]

Originally Posted by Martin9645

The carb is 56 Years old (Carter AFB)

I thought they used the Thermoquad originally, but regardless, if it's an ancient Carter you would be better off replacing it with a modern EB.

Assuming that you still have the original iron manifold, while you're at it I suggest you also consider changing the intake manifold, for an alloy dual plane manifold such as the Edelbrock Performer or the Weiand Action+Plus.

With the right carb it will probably further improve performance and fuel economy, providing the carb is tuned correctly. It will also reduce the weight by 30-40 lbs! Just make sure you have the bonnet clearance for whatever you go with.

I have a 411 S5 with Edelbrock AVS 1812 (800cfm), and a Weiand 8008, with the original stock air cleaner, and that just fits under the bonnet.

You don't need 800cfm for a stock 383 engine.

PS: Did they fit a fuel pressure limiter? Most electric pumps put out more than the 5-6psi that these engines need.